Introduction

A number of radiographic techniques have been described for examining the upper G.I. tract. The double-contrast (DC) examination, popularized by the Japanese, requires a small amount of high-density barium suspension to coat the mucosal surface and air or CO2 gas to distend the lumen. This technique gives excellent definition of the lesser and greater curvatures and the posterior wall of the stomach; however, satisfactory DC images of the anterior wall of the distal stomach and duodenum are very hard to obtain. Even before the development of the DC procedure, it was known that the anterior wall of these structures could be demonstrated en face by filling the stomach and duodenum with a low-density barium suspension and applying graded compression to permit the examiner to "see through" these viscera - the so-called single-contrast graded-compression (SCGC) technique.

The biphasic-contrast examination, introduced in 1977 by Op den Orth, is a method which combines the best features of the DC and the SCGC techniques in one diagnostic procedure. This method is best performed with a single barium suspension that can provide excellent mucosal coating during gaseous distention in the DC phase of the study and also sufficient transparency to permit "see through" of the contrast agent during the SCGC phase. To achieve these goals, we have developed a medium-density barium suspension which can be administered simultaneously with a gas-producing agent in the form of a cold, carbonated drink ("bubbly barium"), which is dispensed from a soda siphon (Soda King, Model 100 Home Soda-Fountain Siphon, Kidde, Inc., Mebane, NC).